Abstract: …The airborne 131I concentration and ground deposition fields were calculated as the database for subsequent thyroid dose reconstruction for inhabitants of radioactive contaminated regions. The small-scale deposition field variability is assessed using data of 137Cs detailed measurements in the territory of Ukraine. The obtained results are compared with available data of radioiodine daily deposition measurements made at the network of meteorological stations in Ukraine and data of the assessments of 131I soil contamination obtained from the 129I measurements.